Windows Performance Team has released Windows Performance Tools Kit to the Windows SDK for Windows Server 2008 and .NET Framework 3.5.

http://www.microsoft.com/whdc/system/sysperf/perftools.mspx

This is the same tool Windows team uses to diagnose Windows performance problem. Along with the tool comes with a 60-page Quick Start Guide. It offers significant details how the system works.

Having a performance problem lately? Fire up Xperf and look at the pretty chart.